Vinyl chloride polymerization EDTA
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In the vinyl chloride suspension polymerization process, does anyone use EDTA? How is it used? What are the consequences if it isn’t used?
It is not used in PVC produced by the ethylene method; some manufacturers may use it in the calcium carbide method. As the desalinated water is fed into the tank, the chelating agent is added as well.
As far as I know, the calcium carbide method isn’t used.
Used in testing； Not applicable in production
EDTA was once used, mainly to increase whiteness. It can be added to the monomer pipeline before adding the monomer.
It was used a long time ago, with a dispersion feeding system being utilized.
A 30-cubic-meter tank is useful; soft water can be directly poured into the tank from a feeding tank.
The calcium carbide process is used in polymer production systems, primarily in cases where the whiteness of PVC resin deteriorates or remains low. It is generally added to water quality regulators to act as a chelating agent for iron in the monomers
During suspension polymerization, a certain concentration of EDTA is added to the saline solution in order to chelate the metal ions present in it, particularly ions such as iron and copper. This prevents these metal ions from entering the polymer during the polymerization process, thereby improving the quality of the product. In the past, this method was used due to the imperfect purity purification processes; nowadays that technology has become mature and reliable, so the practice of using chelating agents to eliminate the effects of metal ions is now rare.
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